Dumbbell



FIG. 1 is a perspective view of a dumbbell according to my new design;

FIG. 2 is a front view of the dumbbell of FIG. 1, the rear view being anidentical image;

FIG. 3 is a side view of the dumbbell of FIG. 1, the other side viewbeing an identical image; and,

FIG. 4 is an end view of the dumbbell of FIG. 1, the other end viewbeing an identical image.

CLAIM The ornamental design for a dumbbell, as shown and described.